The waterfall model is an information technology system development type model initially published in 1970 by Winston W. Royce. Prior to this time, there had been a number of significant malfunctions of IT system type projects; this is due to a lack of proper parameters, procedural approaches and procedural controls of IT project management tasks.

The purpose of this model is to introduce modus operandi into the system design process; as a skeleton for system development it advances consecutively through a succession of phases, preliminarily with system feasibility analysis and concluding up to system release and maintenance.

The name "waterfall" portrays system progress flows from the top to the bottom, like water falling down steps in a waterfall panorama, one phase at a time towards the bottom in a cascading effect.

In the present day, the waterfall model is considered classical and conservative system type model; however, it is indispensable for a fundamental understanding of system development in IT project systems management.

In the waterfall model, system design is broken down into a number of linear and sequential stages, in which system evolution is seen as flowing progressively downwards, through the phases. The waterfall model has distinct goals for each phase of development. In this development method it is not allowed to journey onto the succeeding phase until the operation of the preceding phase has been accomplished.

The output from each phase formed the input to the next phase; therefore, each phase had to be accomplished in turn to maintain the linkage between the inputs and outputs.

A detail waterfall model can be represented as in the following system development life cycle:

Phase I [SYSTEM FEASIBILITY / Justification]

{-----------------------||----------------------------}

Phase II [SYSTEM PLAN / Justification]

{-----------------------||----------------------------}

Phase III [OUTLINE DESIGN / Confirmation]

{-----------------------||----------------------------}

Phase IV [DETAIL DESIGN / Confirmation]

{-----------------------||----------------------------}

Phase V [CODING/ Unit Test]

{-----------------------||----------------------------}

Phase VI [INTEGRATION / Product Confirmation]

{-----------------------||----------------------------}

Phase VII [IMPLEMENTATION / System Test]

{-----------------------||----------------------------}

Phase VIII [OPERATION AND MAINTENANCE / Re Justification]

Here, a system flows through eight different sequential phases, and each phase is segmented into two divisions: the first division covers the task to be carried out in that phase, and second part is the justification or confirmation procedure on that specific work. Within this model, the terms confirmation and justification have specific meanings:

Justification means validation or inspecting whether the result is fit for the operational mission, that is, checking whether the correct product is being build or not. Is the product correct?

Confirmation means verification or inspecting the link between a result and the specification for the result. In other words, a check that the result is being constructed in the correct manner. Is the system structure correct?

The process of building the systems product flows phase to phase with very little interaction in-between two stages, apart from transfer of outputs and inputs between them. The phase progression sequences enforce discipline as every phase has a specific start and end spot, and progress can be categorically acknowledged.

Within more modern system design projects, the water model is in use to mean any chronological representation that is divided into successive phases and which pursue the common structure of the original model. Here, the naming of the phases is not vital, and suitable names can be used for the particular project being undertaken.

The waterfall model retains that system and should move to the next phase only when it's previous phase is completed and perfected. Thus in the waterfall model each phase in a system development life cycle is seen as part of an irreversible succession of events. One phase cannot commence until the previous step has ended. Once a step has been started, there is no reverse back to a prior step.

For instance, "detail design" cannot start until "outline design" has been finished, and program "coding" cannot begin until "detail design" has been completed.

Phases of development in the waterfall model are thus discrete, and there is no leaping back and forth or overlap between different phases.

Appreciations and Criticism of The Waterfall Model:

Appreciation:

The waterfall model provides a clear and easy to follow sequence of activities; it is simple and can be understood without many complications. Furthermore, particular issues on quality management are addressed through the Justification and Confirmation section that is being followed in each phase of the model, and in addition to this, this model will facilitate project management and control by the need to complete each stage before moving to the succeeding phase.

Criticism:

The waterfall model lacks prescribed technique of implementing management control over a project; planning, controlling, and risk management are not enveloped within the model itself. Moreover, forecasting the estimated time and cost are complicated for each stage. The life cycle can take long as the original requirements may no longer be valid, with little possibility for prototyping.

The waterfall model of system development works best when any reworking of products is kept to a minimum and the products remain unchanged. It still remains useful for steady and non-volatile types of projects, and if properly implemented, generates significant cost and timesaving. If the system is likely to go through significant changes and if the system requirements are unpredictable then different approaches are recommended, one such alternate approach is popularly know as the spiral model.

Of It Project Management

Industrial safety equipment is used to reduce the risk of injury, loss and danger to persons, property or the environment in any facility or place involving the manufacturing, producing and processing of goods or merchandise. All around the clock safety of the workers and the industrial safety equipment should be ensured by the employer and the employee. Not all glasses are designed solely for vision correction, but rather for protection, viewing visual information (such as stereoscopy) or simply just for aesthetic or fashion values. Safety glasses are a kind of eye protection against flying debris or against visible and near visible light or radiation. Sunglasses allow better vision in bright daylight, and may protect against damage from high levels of ultraviolet light. Industrial Safety glasses are a kind of eye protection against flying debris or against visible and near visible light or radiation. Eyeglass frames are commonly made from metal, horn or plastic. Lenses were originally made from glass, but many are now made from various types of plastic, including CR-39 or polycarbonate. These materials reduce the danger of breakage and weigh less than glass lenses. Some plastics also have more advantageous optical properties than glass, such as better transmission of visible light and greater absorption of ultraviolet light. Some plastics have a greater index of refraction than most types of glass; this is useful in the making of corrective lenses shaped to correct various vision abnormalities such as myopia, allowing thinner lenses for a given prescription. Nowadays safety glasses can be combined with sun glasses, allowing for eye protection in outside activities from flying debris and ultraviolet light. Scratch-resistant coatings can be applied to most plastic lenses giving them similar scratch resistance to glass. Hydrophobic coatings designed to ease cleaning are also available, as are anti-reflective coatings intended to improve night vision and make the wearer's eyes more visible. Earmuffs are foam filled cushions and pivoting ear cups provide a snug, comfortable fit. Earmuffs are objects designed to cover a person's ears for protection resembling the headphone. They consist of a thermoplastic or metal headband that fits over the top of the head, and a pad at each end, to cover the external ears. They come in two basic kinds: Thermal earmuffs: the original type, worn in winter to keep a person's ears warm. Acoustic earmuffs, also known as ear defenders: cups lined with sound-deadening material, like thermal earmuffs and headphones in appearance, which are worn as hearing protection. These may be carried on a head-band or clipped onto the sides of a hard hat, for easy use on construction sites. Some manufacturers combine headphones with ear defenders, allowing the wearer to listen to music, communication or other audio source and also enjoy protection or isolation from ambient noise. Acoustic earmuffs were created in Italy in 1982. The advantages of earmuffs over earplugs are: Less attenuation variability among users, designed so that one size fits most head sizes, not easily misplaced or lost, may be worn with minor ear infections and can be quickly placed over and removed from your ears.

Both Bharat Bista & Mike Smith1 are contributors for EditorialToday. The above articles have been edited for relevancy and timeliness. All write-ups, reviews, tips and guides published by EditorialToday.com and its partners or affiliates are for informational purposes only. They should not be used for any legal or any other type of advice. We do not endorse any author, contributor, writer or article posted by our team.

Mike Smith1 has sinced written about articles on various topics from Networking, Information Technology and Sales and Negotiation. Did you find this article useful? For more useful tips & hints, Points to ponder and keep in mind, techniques & insights pertaining to Google Adsense, Do please browse for more information at our website :-. Mike Smith1's top article generates over 5400 views. Bookmark Mike Smith1 to your Favourites.

Construction Management Jobs In NcAnd in very technical fields like Construction Management, the smartest often get the best jobs, because companies need the only the best graduates to work for them